Carriage reciprocating mechanism



M. H. ARMS ET AL CARRIAGE RECIPROCATING MECHANISM Aug. 7, 1951 Original Filed Jan. 9, 1947 2 Sheet s-Sheet l A g' 7, 5 M. H. ARMS ET AL 2,563,301

' CARRIAGE RECIPROCATING MECHANISM Original Filed Jan. 9, 1947 2 Sheets-Sheet 2 W iwwifiw Patented Aug. 7, 1951 CARRIAGE RECIPROCATING MECHANISM Merton H. Arms and Paul A. Grobey, Springfield,

Vt., assignors to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont Original application January 9, 1947, Serial No. 721,052, now Patent No. 2,520,267, dated August 29, 1950. Divided and this application December 5, 1947, Serial No. 789,836

Claims.

This invention relates to mechanism for reciprocating a carriage, as, for example, a carriage supporting a grinding wheel, and has for an object to provide such a mechanism by which a nearly constant velocity throughout the traversing stroke may be obtained, such an arrangement being particularly desirable when grinding long holes, or a harmonic motion at high speed which is in some cases desirable when grinding short holes.

A further object is to provide such a mechanism providing continuous adjustment between the harmonic motion and the substantially constant velocity motion as may be desired in any particular case.

Further objects and advantages will appear from a description of an embodiment of the invention shown in the accompanying drawings in which Figure 1 is a fragmentary front elevation of a grinding machine embodying the invention.

Figure 2 is a similar view to a larger scale of a portion of the same.

Figure 3 is a view similar to a portion of Figure 2, but with parts shown in different positions.

' Figure 4 is a detail sectional view on line 4-4 of Figure 2.

Figure 5 is a detail sectional view on line 5-5 of Figure 4.

Figure 6 is a velocity space diagram illustrating the motion of the carriage when the universal joint is set for straight line drive and when it is set for an angular drive at 45.

Referring first to Figure 1, the machine includes a bed I on which is mounted a reciprocating carriage 3 which supports a grinding wheel spindle l, carrying on its projecting end a grinding wheel 8. The carriage 3, for example, may be mounted for reciprocation on a pair of parallel cylindrical guide bars as is more fully shown and described in our application for United States Letters Patent serial No. 721,052, 'filed January 9, 1947, now Patent No. 2,520,267, dated August 29, 1950, for GrindingMachines, of which the present application is a division.

The carriage 3 may be reciprocated by the rocking of an arm 60 fulcrumed in the bed i at BI and normally operatively connected at its upper end to the carriage 3. As shown this construction includes a latch 62 pivoted to the'carriage 3 at 53 and engaging over a cross pin 66 carried by the upper end of the arm and normally held in latching position but releasable by pressure exerted by a bar 255. Further details of this latch connection are not material to this invention and hence are not further described herein, though they are fully shown and described in the parent application Serial No. 721,052 to which reference has heretofore been made.

Power actuating means is connected to the arm 60. In order to avoid contact of the wheel with the work adjacent to the end portions of its stroke for a substantially greater length of time than at its center of motion as with harmonic motion, which is important where the stroke is of substantial length, means may be provided by which the traverse may be adjusted so as not to take place in harmonic motion, but is speeded up somewhat away from the center of stroke and retarded at the center. By this means bell mouthing of the work is avoided. For short strokes harmonic motion is desirable. The arm 60 is connected to a connecting rod 10, which engages a crank pin TI on a crank arm 12. This crank pin is adjustable for throw on the arm 72 and is therefore formed as a flanged sleeve carried by a T bolt 13 (see' Figures 4 and 5) adjustable diametrically lengthwise of the arm 72. For effecting such adjustment, the arm 12 has journaled therein a threaded rod 14 provided with a hand wheel 15 at its outer end, this threaded rod'being threaded through the T bolt I3. The link 10' is made adjustable in length in order to change the limiting end positions of the path of motion of 'the wheel carriage 3, and to this end the link "it! comprises telescopically related sections 80 and 81 which may be clamped in adjusted relation by means of a serrated clamp bar 82 engaging mating serrations in the section 8| and held in position as by a bolt and nut at 83. The arm 12 may be provided with a scale 16 for cooperation with a pointer 84 carried by the link section 80 when the link comprising the sections and 8| is in the dead center relationship to the arm 12 shown in Figure 3, in which position an arrow 85 one guard plate 85 carried by the arm 12 is opposite to an arrow 87 on an eleg ment 88 of a bearing bracket 89 carried by the machine frame V The arm 12 has anintegral shaft portion 90 supported eccentrically on a table I02 clamped.

to the machine frame bracket 93 by a bolt I03 in a clearance hole in the table. 'The table, 102 has pivoted thereto beneath a portionofthe bracket 93, a platform I05 from w i a motor its is V suspended. This motor is connected through belt ID! with a belt pulley I08 fixed'to a worm shaft H0 which is journaled inthe bracket Ill! and which meshes with a 'worih wheel ii car'- ried by a hub portion Il2 which is'secured ;to

the fork 98. The free end of the platform [95? which supports the motor has threaded connection through a nut I 14 with an adjustingbolt H5;

by the adjustment of which the proportion of the weight of themotor effective to tension the belt I01 may be adjusted as desired Itwill be seen that by rotation of the mot or 19G, thejworrn I 19 will be driven, imparting 'rotation to the worm wheel Ill and the fork member of the universal joint and through this, motion will be transmitted to the shaftso in a single direction of rotation and the crankpinjll by which oscilla tion of the wheel carriage actuating arm 60 will be produced. When the shafts 99 and 90 are .5.

in axial alinement, the shaft Sil willbe driven from the shaft 99 in uniform angular velocity,

the shaft 99 being so driven from the motor l e- 6. However, by adjusting the table I92 angularly about the axis of the pivot 91, the shaft 99 is brought out ofv alinement with the shaft 99,

whereupon the shaft 99 will be driven at avariable angular velocity from the shaft, 99 and the maximumextent of this variation, will take place when the shaft 99 is arranged at out of aline- F ment with the shaft 99. When the shafts 99 and 90 are arranged in axial alinement, the motion imparted to the wheel slide will be substantially harmonic as shown by the curve a of Figure 6, and as iswell 7 shown by thecurve b ,(Figure 6) is produced,

the angular velocity of the shaft 99 being lowest when the carrier is nearest to the center of its path of motion. It will be noted that the velocity is substantially linear throughout-the major portion of the traverse between thepoints a: and y. Particularly wherethe stroke is of substantial length, this modification of the velocity of traverse to substantially a-linear value is of sub" stantial importance in grinding to ,close tolerances and it will benoted that this isproduced without the use ofelliptical gears or other com,- plicated k mechanisms which may result in an .uneven or jerky motion of the carriage, and this arrangement makes possible any interme diate setting'or the'tab'le'to prddu eany desire intermediate velocity space diagram ,between driven shaft is rotatedat a uniform angular ve.

4 harmonic motion, curve a, and the substantially straight line motion shown in curve I) of Figure 6.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from its spirit or scope.

1, In combination, a support, a carriage on said support, means guiding said carriage for rectilinear motion on said support, means for moving said carriage comprising a crank shaft, a crank on said crankshaft, connections from said crank to said carriage, and means for turning said crankshaft comprising a drive shaft, means for rotating said drive shaft at uniform angular velocity, a universal joint connecting said shafts. and means supporting said drive shaft so angularly related "to said crank shaft that a nonuniform angular rotation of said crank shaft by said universal joint causes a more uniform rate of motion of saidcarriage than would a uniform angula1" 1'otation of said crank shaft.

2. In combination, a support, a carriage on said support, means guiding said carriage for rectilinear motion on said support, means for moving said carriage comprising a crank shaft, a crank on said crank shaft, a connecting rod connecting said crank and carriage, a table journaled for rocking motion on said support, a motor carried by said table to turn therewith, a'worm shaft parallel to the axis of said motor and driven by said motor, a worm on said worm shaft, a drive shaft, a worm wheel on said drive shaft and with which saidworm meshes, said drive shaft being arranged perpendicular to the axis of said table, said crank shaft being carried by said support and arranged perpendicular to said table axis, a single universal joint connecting said drive and crank shafts, and means for angularly adjusting said table.

3. In combination, a support, a carriage mounted on said support for rectilinear motion, a shaft rotatable at uniform angular velocity, a rotary driven shaft connected to said carriage to reciprocate said carriage by rotation of saiddriven shaft, and driving connections between said drive and driven shafts adjustable to provide either harmonic or non-harmonic motion of said carriage by uniform rotation of said drive shaft.

4. In combination, a support, a carriage mounted on said support for rectilinear motion, a shaft rotatable at uniform angular velocity, a rotary driven shaft connected to said carriage to reciprocate said carriage by rotation of said driven shaft, and driving connections between said drive and driven shafts adjustable to provide either uniform or non-uniform angular velocity of rotation to said driven shaft, the connections between said'driven shaft and carriage imparting harmonic motion to said carriage when saiddriven shaft is rotated at a uniform angular velocity.

5 In combination, a support, a carriage mounted on said support for rectilinear motion, a shaft rotatable at uniform angular velocity, a'rotary driven shaft connectedto saidcarriage to reciprocate said carriage by rotationof said driven shaft, and driving connections ,between said driveand driven shafts adjustabletoyprovide either uniform or non-uniform angular velocity of rotation tosaid driven shaft, the connections between said driven shaft and carriage imparting harmonic motionto said carriage when said 5 6 locity, said non-uniform angular velocity being UNITED STATES PATENTS slower when said carriage is near to its center of Number Name Date motion to impart a more uniform than harmonic 676,700 Roper Julie 18 1901 motion to said carriage when said driven shaft 1,764,161 Flexon et a1 June 1930 is being rotated at said variable angular velocity. 5 1,846,956 Einstein et 551; 1932 MERTON H. ARMS. ,4 1,165 Knapp May 28, 1946 PAUL A. GROBEY.

FOREIGN PATENTS REFERENCES CITED 10 Number Country Date The following references are of record in the 452,153 Germany Nov. '7, 1927 file of this patent: 

